This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Both normal and cancerous cells will be incubated in the presence of PTM-TE probe, after which the cells will be recovered, washed, and re-suspended in fresh culture medium. The cells will be placed in a flat cell-culture type sample container, as recommended by ACERT personnel, placed in the ESR microscopy unit, and ESRM images of individual cells will be obtained. Localization of spin density will be determined within the sub-cellular compartments. These experiments will allow us to determine whether or not cellular uptake of the probes will result in diffuse concentration within the cells, or whether the PTM-TE probe localizes to a particular subcellular location. If this is found to be the case, it may then be possible to modify the molecules so as to direct specific sub-cellular targeting by the probes. We are developing and characterizing LiNc-BuO and other particulate spin-probes that are embedded in a biocompatible and oxygen-permeable polymeric material. As an extension of these efforts, we propose to use the trityl molecular probes PTM-TE and PTM-TC as dopants for oxygen-permeable polymeric materials, including polydimethylsiloxane (PDMS) and silk fibroin. PDMS doped with PTM-TE has been developed in our lab, and these probes are commonly referred to as "SpinChips." We shall use the ESRM capability of ACERT to assist in determining the optimal doping concentration for use with these materials. ESRM will permit us to determine the degree of aggregation of the trityl molecules that may result in spin-spin interaction and artificial line-broadening of the signal obtained - a concern that should be avoided.